JPS5810455A - Lapping machine - Google Patents

Abstract

PURPOSE:To improve yield of products as well as to shorten their processing time in such a way that it is used for processing watch cover glasses, etc., and diamond pellets are provided all over the surface of a lapping fixing machine so as to be processed by means of fixed grinding graules in lieu of the conven- tional free granules. CONSTITUTION:Diamond pellets 10 are provided on a lapping fixing machine. Diamond granules in the diamond pellets 10 are of fixed grinding grains. The size of the granule is approximately 6mu having grinding point of throusands of fine crystals every granule, and during grinding process, by pulverizing and removing the fine crystalline granules, new infinitesimal edge can be produced. Thus, in comparison with the grinding by means of conventional free grinding grains, it offers the grinding speed approximately five times faster.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in lapping machines. Here, we will explain in detail the processing of a watch cover glass as an example.

Figure 1 shows a typical lapping machine. The lapping machine consists of a main body 1, an upper lap surface plate 2, a lower lap surface plate 3, an air cylinder 4 for raising and lowering the upper lap surface plate, and a carrier 5 and 751 for fixing the workpiece.

Conventionally, when grinding a cover glass for a watch, etc., the workpiece is fixed with a carrier 5, sandwiched between the upper lap surface plate 2 and the lower lap surface plate 3, and the abrasive hole d in the upper lap surface plate (Fig. 2) is used. Than,
Processing was carried out while applying free abrasive grains stirred in water.

In the grinding-polishing process, free abrasive grains are used in stages from large-sized free abrasive grains to small-sized free abrasive grains.

The two upper and lower lap plates are 2 to 3 meters long as shown in Figure 2.
Grooves are cut in a grid pattern at intervals of 20 m, and abrasive grain holes 6 are placed in each case so that the upper and lower parts can be replaced. In FIG. 2, only 1/4 part is shown, but the above-mentioned processing is applied to the entire surface.

FIGS. 3(a) to 3(C) are diagrams showing the state of grinding using free abrasive grains 8, in which the free abrasive grains 8 move freely between the workpiece 9 and the lapping surface plate 2.3. As the free abrasive grains 8 rotate, they scrape off the surface of the workpiece. The scraped pieces of the workpiece, sludge, and loose abrasive grains 8 are removed from the grooves 7 of the lapping surface plate in Fig. 2.
It flows down into the tank and is circulated by a pump. Therefore, it is not possible to separate debris or sludge from free abrasive grains 8.
Prone to deep scratches from debris and sludge. As the grinding continues, the free abrasive grains 8 deteriorate and become rounder. For this reason, the grinding speed was not constant, and if grinding was performed for 7.5 hours a day, it had to be replaced every day. As a result, a huge amount of waste is generated, which requires expense and equipment for processing.

When grinding is performed using the above method, the grinding time is 10 minutes or more, and it also takes time to clean the loose abrasive grains 8 attached to the workpiece after grinding. There is a problem that side time is long.

Therefore, the shortcomings of conventional grinding methods using free abrasive grains can be summarized into the following five points.

■Grinding ability decreases due to deterioration of free abrasive grains and sludge.

■Grinding time is long.

■If the sludge and free abrasive particles cannot be separated, scratches may occur.

■Expenses are required to process waste.

■Free abrasive grains need to be replaced every day.

Therefore, the present invention has been made in view of the above drawbacks.
The objective is to provide a lapping machine that reduces grinding and polishing time, improves yield, and saves costs.

The gist of the present invention is as described in the claims below. A preferred embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 4 shows a lapping surface plate provided with diamond pellets 10, and the diamond particles in the diamond pellets are fixed abrasive grains as opposed to the above-mentioned free abrasive grains. Figure 5 shows diamond crystal grains. The size of the particles shown in the figure is approximately 6μ, and each particle has several thousand fine crystal grinding points, and as the fine crystal particles are ground and removed during the grinding process, new fine crystals are created. A sharp edge is created. Therefore, compared to conventional grinding using free abrasive grains, it was possible to obtain a grinding speed approximately five times faster. Moreover, since free abrasive grains are not required, it is sufficient to use water as the grinding fluid. Sludge is removed by passing the waste liquid through a centrifuge, so water can be recycled and scratches can be prevented.

Figures 6(a) to 6(c) are diagrams showing the grinding process using diamond pellets. The grinding points of the diamond particles 11 create new grinding points one after another while grinding the workpiece 9. At this time, the pressure applied to the upper surface plate 2 is increased to 12 by increasing the air pressure of the upper lap surface plate lifter 4, and the grinding time is
It will be further shortened.

In particular, in the present invention, after grinding to the required dimensions, the upper lap surface plate, which has been pressurized up to now, is brought to a reverse pressure 13 by adjusting the air pressure, thereby reducing the pressure applied to the workpiece 9. If the lapping machine continues to operate in this state, the grinding will not progress and only the uneven convexes and convexities on the surface of the workpiece will be removed.

That is, this is the first step of polishing, and if this state is continued for 5 to 10 minutes, the surface becomes smooth and transparent. Therefore, the time required for the next step of polishing is shortened.

As described above in detail, the present invention provides effects such as shortening the grinding-polishing time, eliminating free abrasive grains, and improving yield.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a general grinding machine for double-sided simultaneous grinding and polishing, Fig. 2 is a partially omitted view of a conventional upper and lower lap surface plate, and Fig. 3 is a grinding machine using free abrasive grains. 4 is a partially omitted view of a lapping surface plate provided with diamond pellets according to the present invention, and FIG. 5 is an enlarged cross-sectional view showing the state of polycrystalline diamond 3...
Lower lap surface plate, 5... carrier, 10... diamond pellet.

Claims (1)

[Claims] A lapping machine for double-sided simultaneous grinding and polishing having two upper and lower lapping plates and a carrier, characterized in that diamond pellets are provided on the entire surface of the lapping plate.